Device for adjusting a typewriter platen



A. SALZBERGER 2,986,259

DEVICE FOR ADJUSTING A TYPEWRITER PLATEN Filed July 21, 1960 May 30, 1961 DEVICE Fon ADJUSTING A TYPEWRITER PLATEN Filed July 21, 1960, Ser. No. 44,315

8 Claims. (Cl. 197-149) This invention relates to` improvements in typewriters for regulating the distance of the platen from the type impression point, so as to enable the typewriter to be used for various types of paper or for various numbers of copies while achieving optimum legibility of the typewritten material.

In typewriter-office machines, particularly typewriters used for general office purposes, the layer thickness of the paper received by the platen and to be printed on varies in many cases, the layer thickness depending on the thickness of the paper to be typed and on the number of desired carbon copies.

In order to achieve a clear print on the last copy of the desired number of copies to be typed, the typist very often must use more force on the typewriter keys forthe type bars with a fixed adjustment of the platen, with the resulting danger that, because of the 'thicker paper layer on the platen and the resulting reduction of the distance of the parallel plane touching the paper layer to the plane of the impact plate, the respective type pierces the original sheet and the underlying copy sheets.

It is conventional in typewriter-office machinestoadjust the tension of the return springs for the type bars by an adjusting element in order to adapt the intensity of the stroke to the personal touch of the typist. This design also oiers the possibility of regulating within certain limits the sharpness of the print with constant striking force according to the number of copies to be made.

Further, typewriter-office machinesy have ibeen constructed wherein the platen is adjustably supported in an inner carriage. It has also been suggested to make* the carriage displaceable with regard to the striking point by displacing the guide rail. This design, however, is only suitable for short carriages.

The invention relates to an improved device for regulating the stroke of the types to the thickness of the paper received by the platen, which permits regulation within wide limits and which is independent of the individual touch of the respective typist.

According to the invention the carriage is guided parallel to itself on the machine frame in a typewriter-oce machine with the carriage passing before the striking point with the platen receiving the papers to be typed.

In carrying out the invention the carriage is guided with grooved rollers on a guide rail of thezmachine frame and the carriage can be swung over an eccentric drive about the axis of the guide rail. Thus, the carriage carrying the platen can be moved back and forth in its entirety with regard to the type impact plate. yThe rollers of the carriage are received in gimbals by the carriage, so that their rotation about the axis ofthe guide rail does'not influence the levelof the platen with regard to the pressing point of the types.

It is, therefore, the primary object of the present invention to provide means for adjusting the position of a platen with respect to the type in a typewriter, so as to United StetsSPeref-O Patented May 30, 1961 of the copies being legible to an improved degree.

It is a further object of the presentinvention to provide means for visually indicating the position of an adjusting bar and cam means associated therewith which is .a further visualindication of the position of the platen. j

Still a further object and feature of the invention resides in the provision of a device for regulating the position of a platen with respect to the type of a typewriter that is strong and durable, simple in construction and manufacture, capable of being incorporated in various existing types of typewriter machines and which is simple to operate by utilizing only a single knob.

These, together with the various ancillary objects and features of thisV invention which will become apparent as the following description proceeds, are attained by this device, a preferred embodiment of which is shown in the accompanying drawing, by way of example only, wherein:

Fig. 1 is a partial sectional view of a portion of a typewriter illustrating the invention as mounted on the frame o f the typewriter;

Fig. 2 is a top plan view of a portion of the invention ywith parts thereof being shown in section to illustrat other parts in detail; and

Fig. 3 is a partial elevational view illustrating the indicating means incorporated in the invention.

With continuous reference to the accompanying drawing, wherein like reference numerals designate similar parts throughout the various views, it is to be noted that the invention is shown in conjunction with a typewriter but it is to be understood that this invention can be used in connection with various types of business machines.

The supporting plate 1, which is detachably received by the machine frame, receives in known manner a guido rail 2 which funchions as a rear support and guide of the machine carriage 3 whose front side carries cylindrical rollers 42 which bear on a second. guide rail 44.

The rear wall 12 of the machine carriage 3 is provided with two pairs of projecting bearing brackets 13, between each of which is pivotally mounted one tilting frame or gimbal 5 between coaxial screw bolts 14 which extend parallel to the guide rail 2.

Each tilting frame 5 carries between adjusting screws 15 a grooved roller 4 which has the purpose of guiding the machine carriage on the guide rail. Guide plates 46 extending from the rear wall 12 engage the guide rail at the bottom thereof and prevent the carriage from being lifted.

Each tilting frame 5 carries angular adjusting arms 6,

whose free ends are engaged by a spring 16. The springs` 16 have their other ends suspended on holding bolts 18 which are fixed to the machine carriage 3. The side walls 8 of the carriage 3 have journalled therein an adjusting bar 9 which is operated by a knob 10. The adjusting bar 9 is arranged between the adjusting arms 6 and the rear wall 12 of the carriage 3 above the rollers 4 and carries adjacent to the adjusting arms 6 cam disks 11. Each of the adjusting arms 6 is held under the action of the springs 116 and by means of an adjustable stop 17, so as to b e inuenced by the position of the respective cam disk l11.` n l Dueto this design, the swinging position of the tilting frame 5jwith respect ot the machine frame canv be changed by turning the adjusting bar 9 through knob 10, thus adjusting the angular position of the rollers 4 to the vertical axial plane through the guide rail 2. The rollers 4 are thus swung back or forth from the vertical axial plane through the guide rail 2 by turning the adjusting bar 9.

This way the carriage 3 with all its parts carried by it, particularly the platen 7, is shifted back and forth parallel to itself with regard to the guide rail 2, and the supporting plate 1 as well as the entire machine frame, so that the distance of the vertical tangential plane through the striking point of the types on the platen from the vertical plane through the impact plate for the type bars is changed.

The carriage 3 can thus be so adjusted corresponding to the diameter of the platen and of the respective thickness of the paper sheet, so that a satisfactory print of the types on all paper sheets can be effected.

In order to secure the adjusting bar in its respective position, there is provided next to one side wall 8 of the carriage 3 a notched segment 19, which is engaged by a locking spring 20 fixed to the carriage 3.

A pulley 21 xed on the adjusting bar 9 has entrained thereabout a traction rope 22 Which is rigidly connected at the other end thereof with a rotatable pulley 23 rotating on the bearing bush for the axle of the platen 7. The pulley 23 carries a segment 24, shown in Fig. 3, which can be turned behind a window 26 of the cover 27 of the carriage 3. The pulley 23 is inenced by a return spring 28.

When turning the adjusting bar 9, the traction rope 22 is thus carried along or relaxed, so that the pulley 23 is turned with the indicating segment against the loading spring 28 and under its influence opposite to the direction of rotation of the adjusting bar 9, and the respective setting can be seen through the window 26.

Thus, it can be seen that there has been disclosed a device for regulating the position of a platen 7 with respect to the type in a typewriter having a frame 1. The device includes a guide rail 2, a carriage 3 having the platen 7 mounted therein, rollers 4 movably mounted on the guide rail 2, gimbal means 5 connecting the rollers 4 to the carriage 3, adjusting arms 6 secured to the gimbal means 5, an adjusting bar 9 journalled in the carriage 3, cam means 11 on the adjusting bar 9, and :resilient means 16, v17 secured to the carriage by way of a bolt 18 and to the adjusting arm 6 for urging the adjusting arm 6 towards the cam means 11, so that the adjusting arm 6, the gimbal means 5, 'the rollers 4, and the platen 7 will be intiuenced in that position by the position of the adjusting bar 9.

Various changes and modiiications may be made without departing from the spirit and scope of the present invention and it is intended that such obvious changes and modifications be embraced by the annexed claims.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

'1. A device for regulating the position of a platen with respect to the type in a typewriter having a frame, said device comprising a guide rail, a carriage having a platen mounted therein, rollers movably mounted on said guide rail, gimbal means connecting said rollers to said carriage, adjusting arms secured to said gimbal means, an adjusting bar journalled in said carriage, cam means on said adjusting bar, and resilient means secured to said carriage and said adjusting arms for urging said adjusting arms toward said cam means so that said adjusting arms, said gimbal means, said rollers and said platen are influenced in their position by the position of said adjusting bar.

2. A device according to claim 1, including means for locking said adjusting bar in a selected position.

3. A device according to claim 1, including a notched segment xed to said adjusting bar, and a locking spring fixed to said carriage and engaging said notched. segment for locking said adjusting bar in a selected position.

4. A device according to claim 1, wherein said rollers are grooved for seating on said guide rail, and guide plates secured to said carriage underlying said guide rail to prevent said carriage from being lifted.

5. A device according to claim l, including an indicating mechanism connected to said adjusting bar for visually indicating the position of said cam means.

6. A device according to claim 1, wherein said indicating mechanism includes a first pulley fixed to said adjusting bar, a second pulley having an indicator fixed thereto, said carriage having a window therein, said indicator being positioned adjacent said window, and a rope entrained over said iirst pulley and secured to said second pulley for moving said indicator to correspond to the position of said adjusting bar and cam means.

7. A device for regulating the position of a platen with respect to the type in a typewriter having a frame, said device comprising a guide rail, a carriage having a platen mounted therein, rollers movably mounted on said guide rail, gimbal means connecting said rollers to said carriage, adjusting arms secured -to said gimbal means, an adjusting bar journalled in said carriage, cam means on said adjusting bar, resilient means secured to said carriage and said adjusting arms for urging said adjusting arms toward said cam means so that said adjusting arms, said gimbal means, said rollers and said platen are inuenced in their position by the position of said adjusting bar, a notched segment Alixed to said adjusting bar, a locking spring fixed to said carriage and engaging said notched segment for locking said adjusting bar in a selected position, and an indicating mechanism connected to said adjusting bar for visually indicating the position of said cam means.

8. A device for regulating the position of a platen with respect to the type in a typewriter having a frame. said device comprising a guide rail, a carriage having a platen mounted therein, rollers movably mounted on said guide rail, gimbal means connecting said rollers to said carriage, adjusting arms secured to said gimbal means, an adjusting bar journalled in said carriage, cam means on said adjusting bar, resilient means secured to said carriage and said adjusting arms for urging said adjusting arms toward said cam means so that said adjusting arms, said gimbal means, said rollers and said platen are influenced in their position by the position of said adjusting bar, a notched segment fixed to said adjusting bar, a locking spring fixed to said carriage and engaging said notched segment for locking said adjusting bar in a selected position, and an indicating mechanism connected to said adjusting bar for visually indicating the position of said cam means, said indicating mechanism including a 'rst pulley xed to said adjusting bar, a second pulley having an indicator fixed thereto` said carriage having a window therein, said indicator being positioned adjacent said window, and a rope entrained over said first pulley and secured to said second pulley for moving said indicator to correspond to the position of said adjusting bar and cam means.

References Cited in the tile of this patent UNITED STATES PATENTS 2,062,236 Schuler Nov. 24, 1936 FOREIGN PATENTS 214,732. Great Britain Apr. 28, 1924 

